Enable and disable Button according to the text in EditText in Android

问题

I want to disable by Button if the words in the EditText is less than 3 words, and if the words in the EditText are more than 3 words then I want to enable it so that it can get Clicked.

Can anyone help me here?

回答1:

You have to addTextChangedListener to your EditText

Like this:

yourEditText.addTextChangedListener(new TextWatcher() {
      @Override
      public void afterTextChanged(Editable arg0) {
         enableSubmitIfReady();
      }

      @Override
      public void beforeTextChanged(CharSequence s, int start, int count, int after) {
      }

      @Override
      public void onTextChanged(CharSequence s, int start, int before, int count) {
      }
    });

In that method, you should do like this:

 public void enableSubmitIfReady() {

    boolean isReady = yourEditText.getText().toString().length() > 3;    
    yourbutton.setEnabled(isReady);
  }

Hope it helps.

回答2:

The problem with using afterTextChanged alone is at application start it can't disable the button initially until you start typing to your EditText.

This is how I implemented mine and it works great. Call this method inside your Activity's onCreate method

void watcher(final EditText message_body,final Button Send)
{
    final TextView txt = (TextView) findViewById(R.id.txtCounter);
    message_body.addTextChangedListener(new TextWatcher()
    {
        public void afterTextChanged(Editable s) 
        { 
            txt.setText(message_body.length() + " / 160"); //This is my textwatcher to update character left in my EditText
            if(message_body.length() == 0)
                Send.setEnabled(false); //disable send button if no text entered 
            else
                Send.setEnabled(true);  //otherwise enable

        }
        public void beforeTextChanged(CharSequence s, int start, int count, int after){
        }
        public void onTextChanged(CharSequence s, int start, int before, int count){
        }
    }); 
    if(message_body.length() == 0) Send.setEnabled(false);//disable at app start
}

回答3:

You can do what @Udaykiran says but use arg0.length() instead.

The Editable also contains the length of the content of the TextEditor that was changed

回答4:

Most Easy Solution

This is very easy in Data-Binding. You can directly handle button state in XML depending on EditText.

android:enabled="@{etName.text.length() > 5 &amp;&amp; etPassword.text.length() > 5}"

Here & is HTML entity which denotes to &.
Here etName & etPassword are corresponding ids for name & password EditText.

Sample XML -

<LinearLayout
    >

    <EditText
        android:id="@+id/etName"
        />

    <EditText
        android:id="@+id/etPassword"
        />

    <Button
        android:enabled="@{etName.text.length() > 5 &amp;&amp; etPassword.text.length() > 5}"
        />

</LinearLayout>

来源：https://stackoverflow.com/questions/8225245/enable-and-disable-button-according-to-the-text-in-edittext-in-android

标签

android

button

android-edittext